IS 3708 (Part 9) :2005 ISO 247:1990 mm n I$mi cml-ea&Fmf3q%THrfM . Indian Standard METHODS PART 9 ( OF TEST FOR NATURAL RUBBER LATEX DETERMINATION OF TOTAL ASH Second Revision) ICS 83.060 (3 BIS 2005 BUREAU MANAK OF BHAVAN, INDIAN STANDARDS SHAH 110002 ZAFAR MARG 9 BAHADUR NEW DELHI ~dy 2005 Price Group 2 Rubber and Rubber Products Sectional Committee, PCD 13 NATIONAL FOREWORD This Indian Standard (Part 9) (Second Revision) which is identical with ISO 247:1990 `Rubber -- Determination of ash' issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendations of the Rubber and Rubber Products Sectional Committee and approval of the Petroleum, Coal and Related Products Division Council. The text of ISO Standard has been proposed to be approved as suitable for publication as an Indian Standard without deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following: a) Wherever the words `International be read as `Indian Standard'. Standard' appear referring to this standard, they should b) Comma (,) has been used as a decimal marker while in Indian Standards, practice is to use a point (.) as the decimal marker. the current In this adopted standard, reference appears to the following International Standard for which Indian Standard also exists. The corresponding Indian Standard, which is to be substituted in its plac'e, is listed below along with its degree of equivalence for the edition indicated. However, that International Standard cross-referred in this adopted ISO Standard, which has subsequently been revised, position in respect of that latest ISO Standard has been given: International Standard Corresponding Indian Standard Degree of Equivalence Technically equivalent ISO 248:1979 Determination content Rubbers, of volatile raw -- matter IS 3660 (Part 2) :1985 Methods of test for natural rubber: Part 2 Determination of volatile matter (NR: 2) (second revision) [Supersedes a portion of IS 3660 (Part 51) : 1972] The Technical Committee responsible for the preparation of this standard has reviewed the provisions of the following international Standards and has decided that they are acceptable for use in conjunction with this standard: International Standard Title Rubber and Iatices -- Nomenclature Rubber, raw -- Sample preparation ISO 1629:1987 ISO 1796:1982 In reporting the results of a test or analysis made in accordance with this s{andard, if the final value, observed or calculated, is to be rounded off, it shall be done in accordance with IS 2:1960 `Rules for rounding off numerical values (revised)'. IS 3708 ISO (Part 91:2005 247:1990 Indian Standard METHODS OF TEST FOR NATURAL RUBBER LATEX PART 9 ( DETERMINATION OF TC)TAL ASH Second Revision) 1 1.1 the Scope This International of Standard ash from specifies raw two methods for were valid. All standards agreements t; investigate are subject to revision, Standard and parties to are encouraged based on this International the possibility of applying the most recent aditi;ns Members of IEC and ISO meinStandards. valid International determination rubbers, compounded to raw. in 1.2 and of the standards indicated below. tain registers of currently rubbers families and vulcanizates. or vulcanized described The methods rubbers are i3DDhCabk as restricted compounded of the M', `N, O, R and U ISO 248: 1979, in ISO 1629, except Rubbers, raw ­ Determination of volatile 1.3 below. This international pound who elevated Standard does not cover the interpretation chemical content of matter content. ISO 1629: 1967, Rubber and Iatices ­ Nomenclature. the ash results as to the inorganic or vulcanizate. temperatures, has to be aware of a comat ISO 1796:1962, This is the responsibility of the behaviour of the analyst, of rubber additives Rubber, raw ­ Sample preparation. 1.2 from Method A shall not be used for the determination or vulcanized rubbers containing of ash chlorine, 3 3.1 Principle Method A compounded or iodine. bromine 1.3 Method B shall be used for compounded rubbers containing chlorine, bromine or iodine. rubbers. or vulcanized It shall not be A weighed After test portion is heated in a crucible over a gas burner. of the volatile ma-r decomposition where products, the to a muffle furnace it is heated un- expulsion used for uncompounded crucible is transferred til all the carbonaceous mass is attained. has been burnt off and constant 1.4 Lithium and fluorine compounds comoounds, may aivirm react with silica crucibles Platinum to form volatile crucibles low ash results. shall be used for ash;ng f~uorine-containing rubbers. 3.2 Method B of off and lithium-polymerized A weighed test portion is heated in a crucible in the presence matter has been burnt 1.5 The two methods of ashing do not give identical results in all cases, and it is necessary to state in the test report the method of ashing employed, sulfuric acid, first by means of a gas burner and then in a muffke furnace until all the carbonaceous mess is attained. and constant 2 The Normative following references standards contain provisions which, through 4 provisions of this International indicated Reagent acid (for method B only), analytical grade, reference Standard. in this text, constitute At the time Sulfuric of publication, the editions Q 1,64 g/cm3. 1 IS 3708 ISO (Part 9) :2005 247:1990 5 Apparatus laboratory apparatus and the following: sition products have residue been substantially Transfer maintained expelled and * a dry and its 25 `C carbonaceous Ordinary contents remains. the crucible at 550 `C to the muffle furnace, 5.1 Crucible, of porcelain, silica or platinum, rubbe~, of capacity it is permit- (see, however, the note), leaving the door of the furnace slightly open to provide sufficient air to oxidize the carbon. Continue heating until the carbon Remove is completely the crucible oxidized and a in the heat the 25 `C ­ approximately test portion. 50 ems. For raw synthetic of minimum capacity ted to use a crucible 25 cms per gram of clean ash is obtained. from the furnace, desiccator and weigh maintained allow and ita contents temperature Then allow to cool to ambient to the nearest again for about 0,1 mg. 5.2 square Heat-resistant, thermally the crucible below insulating 5 mm, (5.1). board, with 10JI mm a central of crucible furnace, and its contents 30 min in the muffle temperature in the and of thickness shall project approximately at 550 "C + 25 "C (or 950 "C * to cool to ambient hole to accommodate the crucible About two-thirds see the note), desiccator not differ from the board. and re-weigh to the nearest 0,1 mg. This mass shall mass by more than 1 mg in the is pro- the previous case of raw rubbers or by more than 1 % relative to the amount 5.3 Bunsen burner, or similar type of gas burner. of ash for compounds not fulfilled, repeat cedure and vulcanizates. the heating, between cooling If this requirement and weighing weighings 5.4 Muffle furnace, air flow fitted with a flue and with provision for through the door the furnace. (This may be of opening. ) A temperature- until the difference two successive controlling achieved controlling 550 `C the meets this requirement. NOTE ­ For compounds and 950 "C + 25 `C may be used. vulcanizates, a temperature of by adjusting device is required to maintain a temperature + 25 `C or 950 `C + 25 `C. 7.2 Method B size for about at in a 6 6.1 Preparation of the test portion Heat the clean empty crucible (5. 1) of appropriate 30 min in the muffle allow furnace (5.4), 950 "C + 25 `C, desiccator to cool to ambient maintained temperature Test portions of raw natural rubber shall be cut from the homogenized piece prepared in accordance with ISO 1796. of raw synthetic obtained content rubbers shall be cut from ISO 248. the of dried rubber after carrying in accordance out the determination with and weigh to the nearest 0,1 mg. Take a test portion or vulcanizate and weigh Test portions volatile matter of about 1 g to 5 g of the compound to the nearest 0,1 mg. Place the test portion in the crucible and pour about 3,5 cms of the concentrated over it so that the rubber is completely sulfuric acid (clause 4) Place the crucible thermally insulatwetted. 6.2 and its contents in the hole in the heat-resistant, Test portions of rubber compounds shall be comminuted ing board (5.2) and heat gently with propar ventilation. excessively, or crumbed When a dry, the reaction carbonaceous its contents to becomes residue the more gentle, withdraw by hand. the burner in a hood for If, during the initial reaction, the mixture swells the flame to avoid poesible lose of material. increase the the heat and at 6.3 Test portions of vulcanizates shall be sheeted by hand. on a mill or comminuted from the burner until the excess sulfuric acid is volatilized remains. muffle Transfer crucible 6.4 Care shall be taken to ensure that test portions of rubber compounds and vulcanizates are representative of the sample. and furnace, maintained 950 "C * 25 "C, and heat for about 1 h until all the carbon is completely oxidized and a clean ash is obtained. Remove the crucible and its contents temperature from the furnace, allow to cool to ambient in a desiccator furnace, and weigh to the nearest again for about and re- 7 7.1 Procedure Method A size for about at in a 0,1 mg. Then heat the crucible and its contents 30 min in the muffle weigh maintained allow to cool to ambient temperature at 950 "C ~ 25 `C, in the desiccator Heat the clean empty crucible (5. 1) of appropriate 30 min in the 550 `C t 25 `C, desiccator vu Icanizate, muffle furnace (5.4), allow to cool to ambient to the nearest 0,1 mg .:" mass by more than 1 `Yo cooling two and sucof between maintained temperature If this mass differs from the previous relative weighing cessive ash. to the amount procedure weighings until the of ash, repeat the heating, difference 1 YO relative and weigh to the nearest 0,1 my. Take a test portion rubber or and in according to the mass of ash to be expected, in the hole in the heat-resistant, Heat the crucible If any material of about 5 g of raw rubber or 1 g to 5 g of compounded weigh to the nearest 0,1 mg. Place the weighed the crucible mounted insulating board (5.2). is less than to the amount test portion thermally gently with the burner or (5.3) in a hood for proper ventilation, ber does not ignite. frothing, repeat the above procedure taking care that the rubis lost due to spurting with a new test portion. 8 The Expression ash content of results is given, as a percentage by mass, by the formula When the rubber has decomposed increase the heat from the burner to a charred mass, gradually until the volatile decompo- mz ­ ml X 100 mO 2 IS 3708 (Part !3J :2005 ISO 247:19913 where rrro ml is the mass, in grams, is the mass, in grams, is the mass, in grams, of the test portion; of the empty of the crucible crucible; and ash, b) a reference to this International Standard; c) the method employed -- method A or method B; mz d) the temperature used and the reason A; for its choice if 950 "C is used for method 9 Test report e) the ash content of the product tested, as a percentage the following particulars: of the piece or f) the date of the test. . by mass; The test report shall include a) all details required for full identification sample; 3 Bureau of Indian Standards BIS is a statutory institution established under the Bureau of /ndian Standards Act, 1986 to promote harmonious development of the activities of standardization, marking and quality certification of goods and attending Copyright to connected matters in the country. 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